California Air Resources
Board scientists have sent a letter to Carnegie-Mellon University (CMU)
rebutting a report that warns of added lead pollution from the increased
use of electric-powered vehicles.

According to the letter
signed by Tom Cackette, ARB chief deputy executive officer, the report
compares the total discharges of lead to air emissions resulting in an
overestimation from lead smelting and battery development facilities of
between 44 and 1000 times. In addition, the Carnegie-Mellon report incorrectly
portrays the development of electric-powered vehicles as dependent on today's
lead-acid battery as the power source of tomorrow's cars.

"While lead-acid
batteries have been the dominant power source for electricity in motor
vehicles since before World War II, few experts expect them to be widely
used in future electric vehicles," said John Dunlap, Air Resources
Board chairman.

ARB staff determined
that Carnegie-Mellon researchers used questionable assumptions and outdated
data to determine battery recycling and lead smelting emissions. For example,
ARB researchers point to CMU assertions which rely on US Bureau of Mines
data that includes 20 years of uncontrolled emission rates. Using that
complete data set CMU concluded that emissions from smelting operations
were 44 times greater than those actually emitted by a modern facility.

In addition, ARB scientists
claim that CMU may be as much as 1000 times off in their estimate of lead
emissions from early EVs. Most early EV batteries will be recycled in California
where secondary smelters that emit only about 0.002 percent of the lead
used instead of the 2 percent of the total rate estimated by CMU.

The use of recycled
lead is also important when measuring emissions because about 45 times
less lead is released when recycled lead is used to build batteries than
when newly mined lead is used. Presently, California recycles about 95
percent of all batteries and 85 percent of a new battery consists of recycled
lead.

ARB scientists also
found that Carnegie-Mellon employed pessimistic assumptions about present
and future electric vehicle battery performance and usage. The ARB letter
cites information from the Acurex Corporation and CalStart that estimates
that about one-half of all electric vehicles built in 2000 will use lead-acid
batteries. That figure drops to only about 10 percent of all batteries
being lead-acid in 2010.

The ARB's concerns were
also expressed by scientists from Argonne National Laboratories in a May
30, 1995 letter to Science Magazine. The Argonne letter cites errors in
the CMU study that overestimate airborne lead emissions by up to six times
and the amount of lead needed in modern batteries by about three times.

The Argonne letter signed
by Linda Gaines, Ph.D and Michael Wang, Ph.D states that, "The conclusions
reached in this article (the CMU report) are gross overstatements and based
on obsolete data and extremely pessimistic technology assumptions."

The ARB staff has invited
Carnegie-Mellon University researchers to its July 12, 1995 workshop on
electric vehicle infrastructure at the ARB Mobile Source Laboratories in
El Monte, CA to comment on its report and to discuss other viewpoints.
This workshop is one of a series of public forums to be held over the next
year to provide public input on the ARB's Zero-Emission-Vehicle rule.

Copies of the letter
to Carnegie-Mellon University are available by callling the Air Resources
Board, Public Information Office at (916) 322-2990.